HVAC System - Automatic: Removal & Installation GMC Envoy I

REMOVAL & INSTALLATION

Note. For removal and installation procedures not covered in this article, see A/C HEATER SYSTEM - MANUAL article.

Disconnect negative battery cable. Remove left underdash hush panel. Remove 4 screws attaching knee bolster under steering column. Remove 3 instrument panel accessory trim plate screws. Remove instrument panel accessory trim plate. Remove A/C-heater control module screws. Disconnect electrical connector at back of control module. Remove A/C-heater control module. To install, reverse removal procedure.

1. Remove instrument panel. Remove electronic actuator and A/C-heater system solenoid assembly connectors. Remove electronic actuator. Disconnect actuator vacuum lines. Separate heater case lower half to access air mix door assembly.
2. To install, reverse removal procedure. See VACUUM DIAGRAMS for proper routing of vacuum lines.

1. Remove instrument panel screws/nuts. Roll back instrument panel after loosening it.
2. Disconnect electronic actuator connector. Disconnect air mix door from electronic actuator. see scheme 3 Remove 3 screws attaching electronic actuator to heater assembly.
3. To install, reverse removal procedure. After installation, initialize (calibrate) actuator. See «ACTUATOR CHECK»(ref-40623-S36681717662001011200000) under TROUBLE SHOOTING.

Remove right underdash hush panel. Locate solenoid assembly, on center of A/C-heater assembly, behind instrument panel. Disconnect vacuum lines and electrical connector. Remove screws attaching solenoid assembly to heater case. To install, reverse removal procedure. See VACUUM DIAGRAMS for proper routing of vacuum lines.

Locate sensor in lower center outlet duct. Disconnect sensor harness connector. Twist sensor to remove from duct. To install, reverse removal procedure.

1. Remove driver's side windshield garnish molding by pulling it upward and away from driver's side "A" pillar.
2. Remove left body side trim panel from interior roof line above the driver's door. Unsnap sensor from body panel and disconnect from harness. To install, reverse removal procedure.

Gently pry windshield defrost grille from dash. Disconnect sensor harness connector. (Scheme 1) Twist sensor to remove it from defrost grille. To install, reverse removal procedure.

Scheme 1

1. Remove 3 instrument panel accessory trim plate screws. Remove instrument panel accessory trim plate. Remove radio attaching screws and remove radio.
2. Reach under upper outlet vent duct through radio opening and disconnect sensor harness connector. (Scheme 1) Twist sensor to remove from duct. To install, reverse removal procedure.

Scheme 2

A/C-Heater System Wiring Diagram. Scheme 3